Patch rubber for repairing radial tire, method for repairing radial tire by using the patch rubber, and radial tire repaired by the patch rubber

Abstract

An object of the present invention is to provide: a patch rubber for repairing a radial tire, which patch rubber is capable of preventing troubles from occurring at an early stage in a repaired radial tire to enhance durability of the repaired radial tire; a method for repairing a radial tire by using the patch rubber; and a radial tire repaired by the patch rubber. Specifically, a patch rubber for repairing a radial tire, the patch rubber being constituted of reinforcing cord layers each formed by coating plural reinforcing cords aligned in parallel to each other with rubber, is characterized in that: the reinforcing cord layers constitute a laminate in which they are laminated from one side to the other side; and provided that: i) a region defined by a contour curve connecting adjacent cord ends of the plural reinforcing cords at one end side thereof, another contour curve connecting adjacent cord ends of the plural reinforcing cords at the other end side thereof, and the outermost reinforcing cords in a cord-juxtaposing direction of the plural reinforcing cords represents a reinforcing region in each reinforcing cord layer; ii) one reinforcing cord layer has one reinforcing region; and iii) another reinforcing cord layer, which includes the reinforcing cords having the same cord-extending direction as the reinforcing cords of the one reinforcing cord layer and is laminated on the other side in the layer-lamination direction of the one reinforcing cord layer, has another reinforcing region, the another reinforcing region resides within the one reinforcing region.

1 . A patch rubber for repairing a radial tire, the patch rubber being constituted of reinforcing cord layers each formed by coating plural reinforcing cords aligned in parallel to each other with rubber, characterized in that:
 the reinforcing cord layers constitute a laminate in which they are laminated from one side to the other side; and   provided that: i) a region defined by a contour curve connecting adjacent cord ends of the plural reinforcing cords at one end side thereof, another contour curve connecting adjacent cord ends of the plural reinforcing cords at the other end side thereof, and the outermost reinforcing cords in a cord-juxtaposing direction of the plural reinforcing cords represents a reinforcing region in each reinforcing cord layer; ii) one reinforcing cord layer has one reinforcing region; and iii) another reinforcing cord layer, which includes the reinforcing cords having the same cord-extending direction as the reinforcing cords of the one reinforcing cord layer and is laminated on the other side in the layer-lamination direction of the one reinforcing cord layer, has another reinforcing region, the another reinforcing region resides within the one reinforcing region.   
     
     
         2 . The patch rubber for repairing a radial tire of  claim 1 , further characterized in that:
 the cord-extending direction of the reinforcing cords of at least one of the reinforcing cord layers is orthogonal to the cord-extending direction of the reinforcing cords of the rest of the reinforcing cord layers;   width in the cord-juxtaposing direction of the at least one of the reinforcing cord layers is narrower than length in the cord-extending direction of the outermost reinforcing cords in the cord-juxtaposing direction of the rest of the reinforcing cord layers; and   width in the cord-juxtaposing direction of the rest of the reinforcing cord layers is narrower than length in the cord-extending direction of the outermost reinforcing cords in the cord-juxtaposing direction of the at least one of the reinforcing cord layers.   
     
     
         3 . The patch rubber for repairing a radial tire of  claim 1 , further characterized in that tensile modulus of elasticity of the reinforcing cords of the at least one of the reinforcing cord layers is higher than tensile modulus of elasticity of the reinforcing cords of the rest of the reinforcing cord layers. 
     
     
         4 . The patch rubber for repairing a radial tire of  claim 1 , characterized in that the at least one of the reinforcing cord layers is disposed on the outermost side in the layer-lamination direction in the laminate. 
     
     
         5 . The patch rubber for repairing a radial tire of  claim 1 , characterized in that the reinforcing cords of the at least one of the reinforcing cord layers are aramid cords or glass fiber cords. 
     
     
         6 . The patch rubber for repairing a radial tire of  claim 1 , further characterized in that the at least one of the reinforcing cord layers is thicker than each of the rest of the reinforcing cord layers. 
     
     
         7 . The patch rubber for repairing a radial tire of  claim 1 , further characterized in that:
 the plural reinforcing cords are constituted of: a long reinforcing cord having the longest length in the cord-extending direction among the reinforcing cords; and at least a pair of reinforcing cord disposed on respective sides in the cord-juxtaposing direction orthogonal to the cord-extending direction, of the long reinforcing cord; and   cord ends of the reinforcing cord disposed the closer to the long reinforcing cord are positioned on the more outer side in the cord-extending direction, in said at least a pair of reinforcing cords disposed on respective sides in the cord-juxtaposing direction of the long reinforcing cord.   
     
     
         8 . A method for repairing a radial tire having a tread portion, a pair of sidewall portions extending on the tire radially inner side from respective sides of the tread portion, a pair of bead portions extending on the tire radially inner side from the respective sidewalls, a radial carcass ply including at least one ply formed by plural ply cords coated with ply rubber and extending in a toroidal shape across the bead portions, and a belt ply including at least one ply formed by plural belt cords coated with belt rubber, comprising the steps of:
 attaching, when at least one of the ply cords of the radial carcass ply and the belt cords of the belt ply are broken in at least one of the sidewall portions and the tread portion, a patch rubber for radial tire repair on at least one of a damaged portion of the broken ply cords of the radial carcass ply and a damaged portion of the broken belt cords of the belt ply from at least one of the inner side and the outer side of the tire, for reinforcing the damaged portion; and   using the patch rubber for repairing a radial tire of  claim 1  and attaching it on the damaged portion of the radial tire in the aforementioned reinforcing step.   
     
     
         9 . The method for repairing a radial tire of  claim 8 , further characterized in that the reinforcing step comprising:
 attaching, when the ply cords of the radial carcass ply are broken in the sidewall portion, the patch rubber on the damaged portion of the broken ply cords of the radial carcass ply such that the reinforcing cords of all of the reinforcing cord layers constituting the patch rubber are inclined at an angle in the range of 0° to 30° with respect to the cord-extending direction of the ply cords of the radial carcass ply.   
     
     
         10 . The method for repairing a radial tire of  claim 8 , characterized in that the reinforcing step comprising:
 attaching, when the belt cords of the belt ply are broken in the tread portion, the patch rubber on the damaged portion of the broken belt cords of the belt ply such that the reinforcing cords of at least one of the plural reinforcing cord layers constituting the patch rubber are inclined at an angle in the range of 0° to 30° with respect to the tire circumferential direction and the reinforcing cords of the rest of the plural reinforcing cord layers are inclined at an angle in the range of 0° to 30° with respect to the cord-extending direction of the ply cords of the radial carcass ply.   
     
     
         11 . The method for repairing a radial tire of  claim 8 , further comprising setting dimension of a working area of the patch rubber to be put on a damaged portion of the radial tire from the inner side of the tire, to be 2 to 4 times as large as the damaged portion. 
     
     
         12 . The method for repairing a radial tire of  claim 8 , further comprising setting dimension of a working area of the patch rubber to be put on a damaged portion of the radial tire from the outer side of the tire, to be 1.1 to 1.4 times as large as the damaged portion. 
     
     
         13 . The method for repairing a radial tire of  claim 8 , further characterized in that the rubber constituting the patch rubber for repairing a radial tire is unvulcanized rubber and the patch rubber is vulcanized after completion of the aforementioned reinforcing step. 
     
     
         14 . A repaired radial tire characterized in that the radial tire has been repaired according to the method for repairing a radial tire of  claim 8 .